The overall objectives of the research project are to analyze cellular mechanisms of inherited retinal degeneration in the mouse and rat, diseases which result in photoreceptor cell degeneration at late stages of differentiation due to the action of the autosomal recessive gene, retinal degeneration (gene symbol, rd). Our aim is to define which steps in development are vulnerable so as to produce the different inherited disorders in the two species. The specific goals of the project are to 1) better define the phenotypes by cytological methods, 2) examine photoreceptor-pigment epithelial cell interactions and the physiological behavior of the two cell types with autoradiographic and cytological methods alone and in combination with experimental chimeras and with tissue culture studies, and 3) delineate formal genetic properties of heritable factors controlling the retinal disease.